Re: [PATCH] qla2xxx: Fix the ARM build

[Daniel Wagner <dwagner@xxxxxxx>]

Hi Bart,

On Mon, Jun 08, 2020 at 09:14:03PM -0700, Bart Van Assche wrote:
> diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
> index 42dbf90d4651..edc9c082dc6e 100644
> --- a/drivers/scsi/qla2xxx/qla_def.h
> +++ b/drivers/scsi/qla2xxx/qla_def.h
> @@ -46,7 +46,7 @@ typedef struct {
>  	uint8_t al_pa;
>  	uint8_t area;
>  	uint8_t domain;
> -} le_id_t;
> +} __packed le_id_t;
>  
>  #include "qla_bsg.h"
>  #include "qla_dsd.h"
> @@ -1841,8 +1841,8 @@ typedef union {
>  	struct {
>  		uint8_t reserved;
>  		uint8_t standard;
> -	} id;
> -} target_id_t;
> +	} __packed id;
> +} __packed target_id_t;

This is a bit strange. Why is that only these two definitions need this
treatment? With gcc 6.3.0 on Debian stretch, the compiler did the
right thing for x86_64, ARMv7 and ARMv8. In all cases target_id_t is 2 bytes
long.

Or does this happen because target_id_t is embedded into cmd_entry_t?

Here is the test code:

#include <stdio.h>
#include <stdint.h>

typedef union {
	uint16_t	extended;
	struct {
		uint8_t reserved;
		uint8_t standard;
	} id;
} target_id_t;

int main(int argc, char *argv[])
{
	printf("sizeof(target_id_t) = %zu\n", sizeof(target_id_t));
	return 0;
}

The only thing which is different to the above code is the use uint16_t
instead of __le16. But I thought this should make a difference.

Thanks,
Daniel